1. Technical Field
The present invention relates to a method of manufacturing a translucent ceramic and an orthodontic member, more specially relates to a method of manufacturing a translucent ceramic and an orthodontic member using the translucent ceramic manufactured by the method.
2. Related Art
There has been industrially used a translucent alumina (translucent aluminum oxide) sintered body that makes use of specific properties of ceramics superior in translucency, weather resistance and hardness.
In general, the translucent alumina sintered body is manufactured in the following manner. First, an alumina powder, a sintering agent and an organic binder are mixed together to obtain a mixture. Thereafter, the mixture is put into a mold and then molded by a press molding method, an injection molding method or other molding methods to obtain a green body. A sintered body, that is, the translucent alumina sintered body is obtained by debinding and sintering the green body (Japanese Patent No. 3783445 is an example of the related art.).
The thus obtained translucent alumina sintered body is constituted of polycrystalline alumina and therefore contains a multiplicity of crystal grains.
The translucency of the translucent alumina sintered body depends on a state of the crystal grains. More specifically, if a size of the crystal grains is generally uniform throughout the translucent alumina sintered body, the translucent alumina sintered body exhibits high translucency.
However, a size of crystal grains is ununiform according to a conventional manufacturing method. This poses a problem in that a translucent alumina sintered body obtained by the conventional manufacturing method shows reduced translucency and mechanical properties. Presence of pores in the translucent alumina sintered body is one of factors causing the reduction in translucency.